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mike switzer
mike switzer,
Category: Chevy
Satisfied Customers: 454
Experience:  lead diagnostic tech at Aamco
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Hunter. Just purchased a 2007 suburban with AFM and I have a

Customer Question

Hunter. Just purchased a 2007 suburban with AFM and I have a p0300 code
JA: Thanks. Can you give me any more details about your issue?
Customer: Well i'm concerned about the AFM. I didn't know much about it until after my purchase. As of now I have a p0300 code which is a random misfire
JA: OK got it. Last thing — Chevy Mechanics generally expect a deposit of about $18 to help with your type of question (you only pay if satisfied). Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 8 months ago.
Category: Chevy
Expert:  mike switzer replied 8 months ago.

are you noticing any drivability issues or do you notice a misfire yourself? also what size engine do you have in this suburban?

Customer: replied 8 months ago.
I notice the miss. It's very random. Seems to drive fine other than that.
Customer: replied 8 months ago.
5.3
Expert:  mike switzer replied 8 months ago.

ok thank you for that information. these vehicles have a number of different issues that can cause this in particular. how many miles are on this vehicle?

Customer: replied 8 months ago.
220k. Somebody has been in the motor though. The heads are real clean and the head gaskets look new.
Expert:  mike switzer replied 8 months ago.

the most common failure on those engines with AFM is the valve lifters. although i would pull a spark plug and check its condition first. make sure they are new plugs in there. or at least seem to match the condition of the heads.

Customer: replied 8 months ago.
No valve train noise....
Expert:  mike switzer replied 8 months ago.

they may not make noise but they dont operate properly for the AFM. common failure point is the cam sensor but i would still check the pulgs first. do you have a scanner by chance? or anyway to do a power balance test?

Customer: replied 8 months ago.
I have a handheld scanner
Customer: replied 8 months ago.
I'll pull the plugs tomorrow.
Expert:  mike switzer replied 8 months ago.

is it capable of monitoring data?

Customer: replied 8 months ago.
Expert:  mike switzer replied 8 months ago.

what you will want to do is find where you can see misfire data and while it is running see which cylinder is generating the most misfires while running. it is possible for only one cylinder to misfire and it though a code for random.

Customer: replied 8 months ago.
I'll check it out tomorrow.
Expert:  mike switzer replied 8 months ago.

sounds good let me know what happens

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